1994 Fiscal Year Final Research Report Summary
Studies on the mechanism of osteopenia associated with abnormal endocrine conditions
| Project/Area Number |
05671220
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
HOTOKEBUCHI Takao Kyusyu University, Faculty of Medicine, Assistant Professor., 医学部, 講師 (40190219)
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| Co-Investigator(Kenkyū-buntansha) |
JINGUSHI Seiya Kyusyu University, Faculty of Medicine, Research Associate., 医学部, 助手 (80235829)
IZUMI Toshihiro Kyusyu University, Faculty of Medicine, Research Associate., 医学部, 助手 (90253426)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Endocrine abnormality / Growth hormone / Growth factor / Thyroid hormone / Fracture |
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| Research Abstract |
We studied the relationship between a systemic factor, growth hormone, and local peptide growth factors in the skeletal system in normal rats. Human recombinant growth hormone was injected subcutaneously in 4-week-old rats, and sequential changes of serum growth hormone and gene expression of growth factors were analyzed. Serum growth hormone showed a peak 6 hours after the initial injection. Systemic administration of growth hormone slightly decreased mRNA for transforming growth factor-beta (TGF-beta) in femoral bones 6 hours after the initial injection, but the mRNA returned to the initial level 12 hours after the initial injection. However, there was no statistical significance. On the other hand, mRNAs for basic fibroblast growth factor (bFGF) and insulin-like growth factor-I (IGF-I) increased in response to growth hormone in costal cartilage. These data suggest that local peptide growth factors are regulated by systemic growth hormone.13EA02 : In the second part of our study, fracture healing in the drug-induced hypothyroid rats was studied. The fracture callus had lower torsional stiffness in hypothyroid rats in mechanical testing. Depletion of thyroid hormone also suppressed chondrogenesis and endochondral ossification. Northern analysis revealed decreased expression of alkaline phosphatase and osteocalcin, which are the indices for bone formation. These data suggest the suppressed bone formation in the hypothyroid condition.
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